KR20200014353A - Coated silica particles - Google Patents

Abstract

The present application relates to coated silica particles, compositions containing coated silica particles, and methods of using these compositions in underground strata. The coated silica particles include cationic species that are covalently bound to the outer surface of the particles. The particles may comprise nanoparticles.

Description

Coated silica particles

Priority claim

This application claims priority based on US Provisional Application No. 62 / 514,314, filed June 23, 2017. The entire contents of the provisional application are incorporated herein by reference.

Technical field

The present application relates to coated silica particles, compositions containing coated silica particles, and methods of using the compositions in underground strata.

Recoverable fluids such as hydrocarbons (eg, petroleum or natural gas) and water are frequently found in underground strata. Some underground strata are not strong enough to prevent erosion of underground strata by the flow of fluid through the underground strata. These subterranean strata, often referred to as unconsolidated or incompetent layers, are the remarks of sand, clay or rock (e.g. sandstone, limestone, quartz, zeolite, siltstone, shale or gravel). Contains uncemented or loosely solidified grains. As the fluid flows through the subterranean strata, loose materials, especially sand grains, move with the fluid, causing erosion and collapse of the subterranean strata. Loose sand can accumulate in underground strata, oil wells and drilling equipment. This buildup can cause clogging and reduced flow of recoverable fluid. These entrained sand particles can cause erosion of underground equipment (eg, strainers, liners, valves and pumps), reduce pressure, restrict fluid flow, and contaminate field storage tanks. You can. Loose sand can be carried by the fluid flow to the surface and is removed from the oil well with the fluid being extracted. If a sufficient amount of sand is transported from the production strata, the strata collapse and can seriously damage the well. Thus, problems associated with producing recoverable fluids from the soft underground strata can reduce well productivity and increase well maintenance costs.

summary

The present application discloses a method of controlling sand, especially in non-solidified strata. The method described later herein includes the use of modified charged silica particles in an amount that can aggregate on the sand particles of the unsolidified strata. The positively charged modified particles form a monolayer of solidifying material across the unsolidified strata to provide sand control with the desired permeability characteristics. The sand control treatment materials of the present application include, for example, cationic polymers and colloidal silica particles modified with a pH regulator or ionic strength regulator, optionally disposed in the downhole as a pill. The entire treatment material can be placed in the downhole in a single step operation. This modified silicate material forms a thin monolayer of hard gel around the unsolidified sand particles. The monolayer solidifies the sand grains together and at the same time maintains permeability through the treatment material to facilitate the production of hydrocarbons such as petroleum.

In some aspects, the coated silica particles comprise cationic species non-covalently bound to the outer surface of the particle. The particles may comprise nanoparticles. In some embodiments, the nanoparticles have a diameter of about 1 nanometer (nm) to about 500 nm, a diameter of about 1 nm to about 150 nm, a diameter of about 5 nm to about 50 nm or about 5 nm to about 17 nm It includes the diameter.

In some embodiments, the cationic species comprises a metal cation. In some embodiments, the metal cation comprises two or more oxidation states. In some embodiments, the metal cation may comprise aluminum or iron. The metal cation is a salt or oxide selected from the group consisting of Al ₂ O ₃ , Al ₂ (S0 ₄ ) ₃ , KAl (S0 ₄ ) ₂ , FeCl ₃ and Fe ₂ (S0 ₄ ) ₃ , and hydrates or solvates thereof. Can be formed.

In some embodiments, the cationic species comprises a cationic polymer. Cationic polymers include poly (2-hydroxypropyl-1-N-dimethylammonium chloride), poly (2-hydroxypropyl-1-1-N-dimethylammonium chloride), poly [N- (dimethylaminomethyl)] -Acrylamide, poly (2-vinylimidazolinium bisulfate), poly (diallyldimethylammonium chloride), poly (N-dimethylaminopropyl) -methacrylamide, and combinations thereof. . In some embodiments, the cationic polymer comprises poly (diallyldimethylammoniumchloride). In some embodiments, the molecular weight of the cationic polymer ranges from about 1,000 Daltons (Da) to about 1,000,000 Da, about 1,500 Da to about 500,000 Da, or about 1,500 Da to about 100,000 Da.

In some embodiments, the cationic polymer can be water soluble.

In some embodiments, the cationic species can include quaternary ammonium compounds. In some embodiments, the quaternary ammonium compound is 1,2-ethanediamino, N, N'-bis [2- [bis (2-hydroxyethyl) methylammonio] ethyl] -N, N'-bis ( 2-hydroxyethyl) -N, N'-dimethyl-, tetrachloride.

In some embodiments, the amount of cationic species by weight of the silica particles ranges from about 5 wt% (wt.%) To about 20 wt%. The coated particles may comprise a net positive charge. Non-covalent bonds between the cationic species and the outer surface of the silica particles can include electrostatic interactions. In some embodiments, the electrostatic interaction may include attraction between the negatively charged outer surface of the silica particles and the positively charged cationic species. In some embodiments, the electrostatic interaction can include attraction between the silanol groups or silyloxy anions and the positively charged cationic species on the outer surface of the silica particles.

In some aspects, a method of making coated silica particles containing cationic species non-covalently bound to the outer surface of silica particles comprises the steps of (i) obtaining a colloidal dispersion comprising solid silica particles in a dispersed phase and a solvent in a continuous phase ; (ii) obtaining a cationic species; And (iii) combining the colloidal dispersion of step (i) with the cationic species of step (ii) to obtain coated silica particles. In some embodiments, the solid silica particles can be nanoparticles. The nanoparticles may comprise a diameter of about 1 nm to about 500 nm, a diameter of about 1 nm to about 150 nm, a diameter of about 5 nm to about 50 nm, or a diameter of about 5 nm to about 17 nm.

In some embodiments, the solvent of the continuous phase of the colloidal dispersion comprises water. The amount of dispersed phase in the colloidal dispersion may range from about 5% to about 50% by weight, or the amount of dispersed phase of the colloidal dispersion may be about 15% by weight.

In some embodiments, the methods described herein include adding an inorganic salt solution to the colloidal dispersion. The inorganic salt may contain NaCl. The concentration of inorganic salts in the solution may range from about 1% weight / volume (w / v) to about 30% w / v. The amount of inorganic salt solution may range from about 5% to about 15% by weight relative to the amount of colloidal dispersion.

In some embodiments, the methods described herein can include cationic species in solution form. The solution may comprise an aqueous solution. The concentration of cationic species in the solution ranges from about 10% by weight to about 50% by weight. The amount of cationic species can range from about 0.1% to about 2% by weight relative to the amount of colloidal dispersion.

In some embodiments, the combining step can include adding a cationic species to the colloidal dispersion. After combination, the reaction mixture can be continuously stirred for a time sufficient to obtain coated silica particles. The time may range from about 1 minute to about 15 minutes. In some embodiments, the combining step may comprise noncovalent bonding of the cationic species to the outer surface of the silica particles.

In some aspects, the coated silica particles are prepared by any of the methods described herein.

In some aspects, the curable delayed gelling composition comprises a particulate material comprising the coated silica particles described earlier in this specification. The amount of particulate material in the composition may be about 10% to about 50% by weight, or the amount of particulate material in the composition may be about 15% by weight. The composition may comprise a solvent. The solvent may comprise water. The composition may comprise about 50% to about 90% by weight of water. The pH of the composition may range from about 9 to about 11. The viscosity of the composition may range from about 5 centipoise (cP) to about 10 cP.

In some embodiments, the composition may contain an activator. The activator may comprise a pH adjuster. The pH adjusting agent may contain an ester compound. The ester compound may be selected from the group consisting of formate esters, lactate esters and polylactide resins. The ester compound may be selected from the group consisting of diethylene glycol diformate and ethyl lactate. The ester compound can be hydrolyzed to produce an acid compound. Hydrolysis of the ester compound can occur at temperatures ranging from about 75 ° F. to about 350 ° F. Hydrolysis of the ester compound can occur at temperatures in the range of about 150 ° F. to about 250 ° F. Hydrolysis of the ester compound can reduce the pH of the composition to less than about 5. The amount of pH adjuster in the composition may range from about 0.25% to about 4% by weight.

In some embodiments, the composition can include an ionic strength modifier. Ionic strength modifiers may contain an inorganic electrolyte. The inorganic electrolyte may be selected from the group consisting of KCl, NaCl and NaBr. The amount of ionic strength modifier in the composition may range from about 1% to about 5% by weight. The activator can be configured to promote curing of the composition. The composition can be adjusted to form a hard consolidated gel at least 3 hours after the composition is formed. The composition can be adjusted to form a hard, solidified gel at a temperature in the range of about 75 ° F. to about 350 ° F. The composition can be adjusted to form a hard, solidified gel at a temperature in the range of about 150 ° F. to about 250 ° F. In some embodiments, the composition is considered to be a hard consolidated gel when it cannot flow.

In some aspects, the method of solidifying the soft underground strata includes contacting the soft layer with the curable delayed gelling composition of any one of the compositions described herein to obtain solidified particles of underground particles. The contacting step may further comprise absorbing the curable delayed gelling composition onto the surface of the unsolidified underground particles. Curing of the composition may include solidifying the underground particles as a layer of hard gel on the unsolidified underground particles. Underground particles can include sand grains. The solidified particles of the underground particles may be permeable to the fluid. The solidified particles of the underground particles may have strength to withstand pressure loads of about 700 pound forces (lbf) or more. The solidified particles of the underground particles may have strength to withstand pressure loads of about 700 lbf to about 1000 lbf. The soft underground strata can be penetrated by wells. The contacting may include delivering the curable delayed gelling composition to the soft subterranean layer using coil tubing equipment. The soft underground strata can include a hydrocarbon containing layer. Hydrocarbons may include petroleum. The method may further comprise producing petroleum from the solidified layer.

Certain embodiments of the compositions described herein are designed to solidify loose sand particles in an unsolidified layer. Concentration ranges and ratios of the different components (eg, additives) described herein can be useful to mitigate unwanted sand production that occurs during petroleum production.

In some embodiments, the compositions described herein contain coated nanosilica particles that react in the presence of certain chemical activators disclosed. For example, the composition may comprise coated nanosilica particles, where the viscosity of the coated nanosilica particles increases and eventually gelates in response to certain chemical activators. In some embodiments, the gelation reaction described above can occur under static conditions as well as under dynamic conditions. In various embodiments, the gelling reaction can be independent of shear conditions, temperature conditions, or both. For example, in the absence of the disclosed chemical activator, certain embodiments of the coated nanoparticles will not gel under conditions where the nanoparticles are sheared, exposed to elevated temperatures, or a combination of both conditions. Thus, in some embodiments, the gelling characteristics of the disclosed nanoparticles are unique because the gelation depends on time, temperature and concentration only after the nanoparticles have been exposed to the chemical activators described herein.

Unless defined otherwise, all technical and scientific terms used later in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The methods and materials are described later in this application for use in the present application; Other suitable methods and materials known in the art may also be used. The materials, methods, and examples are illustrative only and not intended to be limiting. All publications, patent applications, patents, sequences, database entries, and other references mentioned later in this specification are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control.

Other features and advantages of the present application will be apparent from the following detailed description and drawings, and from the claims.

The patent or application file includes at least one color drawing executed in color. Copies and color drawing (s) of this patent application publication will be provided by the Office upon submission of the application and payment of the necessary fee.
1 is a schematic of silica nanoparticles coated with positively charged cationic species.
2A and 2B are schemes showing cationic species bound to silanol groups and silyloxy anions on the outer surface of the nanoparticles of FIG. 1.
FIG. 3 is a scheme showing the modification of silica particles using cationic polymer poly (diallyl dimethyl ammonium chloride) (PDADMAC).
4 is a schematic of a consolidated underground strata including nanosilica particles coated with cationic species (eg, PDADMAC).
FIG. 5 is an image showing a test tube containing a sand pack solidified using nanosilica particles coated with cationic species (eg, Clay Master ™ 5C from Baker Hughes).

details

Effective solidification of the soft underground strata is a daunting challenge. The most common method of controlling unwanted sand production involves: (1) filtering the produced fluid through a gravel pack held by a screen, or (2) freezing fluid containing resin and hardener. Use with other chemicals to create an environment conducive to the resin curing reaction. Gravel packing treatments are expensive and generally involve the use of special tools and equipment. In addition, the accumulation of filtered material may cause the gravel and screen to clog after a certain time. Sand control by chemical solidification involves injecting chemicals into the unsolidified strata to provide grain-to-grain solidification. Such conventional sand solidification methods with chemical reagents tend to have relatively uncontrollable set times. If the set time is too long, the fluid may flow into a more permeable region, which may cause the strata to be unevenly processed. If the set time is too short, it may lead to premature curing of the resin, which may cause the treatment to fail.

Accordingly, the present application provides a particulate silica composition and a method of using the composition to provide effective solidification of the soft underground strata and control of loose sand in the strata while maintaining permeability to the recoverable fluid of the underground strata. . Embodiments of silica compositions, and methods of making and using such compositions, are described later herein.

Justice

The terms "for example" and "such as" and their grammatically equivalent terms may be understood to be followed by the phrase "and without limitation," unless expressly stated otherwise.

As used later in this specification, the singular forms “a”, “an” and “the” may include plural referents unless the context clearly dictates otherwise.

As used later in this specification, the term "about" means "approximately" (eg, + or-about 10% of the indicated value).

As used later in this specification, the term "substantially" means at least about 50%, 60%, 70%, 80%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5% , 99.9%, 99.99%, or at least about 99.999% or more.

As used later in this specification, the term “particle” may refer to a composition having a size of about 1 nanometer (nm) to about 1000 micrometers (μm). The term “fine particles” may refer to particles having a size of about 1 μm to about 1000 μm. The term “nanoparticle” may refer to a particle having a size of about 1 nm to about 1000 nm (eg, the diameter of a spherical particle).

As used later in this specification, the term "particle size" (or "nanoparticle size" or "fine particle size") refers to the medium size (eg, based on volume or number) in the distribution of nanoparticles or fine particles. May be referred to. The median size can be determined from the average linear dimension of the individual nanoparticles, for example the diameter of the spherical nanoparticles. The size can be determined by any number of methods in the art, including dynamic light scattering (DLS) and transmission electron microscopy (TEM) techniques. For measurements made using a laser diffraction instrument or equivalent method known in the art, the term “medium particle size” may be defined as the median particle diameter determined on the basis of equivalent spherical particle volume. When the term median is used, it can be understood to describe the particle size that divides the population in half so that 50% of the population is larger or smaller than its size. Median particle size is often described as D50, D (0.5) or D [0.5] or the like.

As used later in this specification, “polymer” may provide a molecular structure that includes one or more repeating units (monomers) in its conventional meaning used in the art, that is, linked by covalent bonds.

As used later in this specification, the term “non-covalent” may refer to an interaction between two or more components in which the bond between components is a non-covalent bond, where an atom of one component is with an atom of another component. This means not sharing a pair of electrons. Non-covalent bonds may include weak bonds such as hydrogen bonds, electrostatic effects, π effects, hydrophobic effects, or van der Waals forces.

As used later in this specification, the term “dispersion” may refer to a system comprising a dispersed phase in a continuous phase. In some embodiments, the dispersed and continuous phases can be in different states (eg, gas, solid or liquid). For example, in some embodiments, the dispersed phase is a solid while the continuous phase is a liquid. In some embodiments, the dispersed phase is a solid particulate material and the continuous phase is a liquid. In some embodiments, the dispersion is a colloid (eg, the particle size of the dispersed phase is in the range of 1 nm to 1 μm).

As used later in this specification, the term "cationic" or "cationic" refers to an amount in which a positively charged atom (or atoms) in a cationic species contains fewer electrons than the number of protons in the nucleus of the atom May refer to a charged species. In one example, the cation is a positively charged metal ion, such as Fe ² , Fe ^{3 +} or Al ^{3 +} . In some instances, the cationic material is an organic molecule containing a positively charged nitrogen or phosphorus atom. In some instances, the cationic molecule is a polymer containing monomers having a positively charged nitrogen or phosphorus atom.

Coated Silica Particles of the Present Disclosure

The present application particularly provides particulate silica materials containing coated silica particles. In some embodiments, the present disclosure provides silica particles coated with cationic species.

Referring to FIG. 1, the coated silica particles comprise a core and an outer surface comprising silicon dioxide (SiO ₂ ), and a cationic species (+) bonded to the outer surface of the silica particles.

2A and 2B, the outer surface of the particle of FIG. 1 is shown, including silanol groups (-Si-OH) and silyloxy anions (-SI-O-) that are non-covalently bound to cationic species.

In some embodiments, the cationic species is noncovalently bound to the outer surface of the particle. With continued reference to FIGS. 2A and 2B, the dotted bonds between cationic species and silanol dipoles / silyloxy anions indicate non-covalent bonds between the cationic species and the outer surface. In some embodiments, the noncovalent bonds between the cationic species and the outer surface of the silica particles include hydrogen bonds, electrostatic interactions, van der Waals forces, or any combination thereof. In some embodiments, the non-covalent bonds between the cationic species and the outer surface of the silica particles include electrostatic interactions such as electrostatic attraction between the positively charged cationic species and the negatively charged outer surface of the silica particles. For example, as shown in FIGS. 2A and 2B, the outer surface of the silica particles is negatively charged due to the presence of silyloxy anions and Si—OH dipoles on the particle surface. These silyloxy anions and Si-OH groups attract positively charged cationic species such as cations of iron or aluminum or quaternary ammonium containing polymers (eg polyquaternium). An example of a particulate silica material comprising negatively charged silica particles is Cembinder® 50 (Akzo Nobel). In some embodiments, the particulate silica material contains cationic (positively charged) silica particles. An example of cationic silica is Levasil® 30-516P (Akzo Nobel).

In some embodiments, the coated silica particles are positively charged. This is possible because the net positive charge of the cationic species bound to the surface of the particle exceeds the net negative charge of the outer surface of the particle. For example, the cationic species may include some positively charged atoms, and some but not all of these atoms (eg, one or two of three) may be silyloxy on the outer surface of the particle. While non-covalently bound to the anion and the Si-OH dipole, the remaining atoms charged in the amount of cationic species do not bond directly to the surface, thus contributing to the overall net positive charge of the particles. One example of a cationic species having more than one positively charged center is poly (diallyl dimethyl ammonium chloride) (PDADMAC, or polyquaternium-6) (CAS Registry No. 26062-79-3). Another example of such cationic species is 1,2-ethanedianium, N, N'-bis [2- [bis (2-hydroxyethyl) methylammonium] of the formula having four quaternary ammonium centers in the molecule Ethyl] -N, N'-bis (2-hydroxyethyl) -N, N'-dimethyl-, tetrachloride:

In some embodiments, all positively charged centers in the cationic species are non-covalently bound to the surface of the silica particles. In other embodiments, the cationic species comprises more than one positively charged center, and some but not all (eg, one or two of three) silica particles are positively charged centers within the cationic species. Non-covalently bound to the surface of the. In some embodiments, some but not all of the positively charged centers in the cationic species comprise at least about 10%, about 15%, about 20%, about 35%, about 50%, of the total amount of cationic species coating the silica particles, The non-covalently bound surface of the silica particles in an amount of about 70%, about 90% or about 99%, and the center of charge in all amounts within the remaining amount of the cationic species coating the silica particles is the outer surface of the silica particles. Non-covalently bound to In any of the embodiments mentioned above, the resulting particles containing the negatively charged material and the positively charged material may have a total net positive charge.

In some embodiments, the amount of cationic species relative to the weight of the coated silica particles is from about 0.5 wt% (wt.%) To about 50 wt%, about 1 wt% to about 40 wt%, about 1 wt% to about 30 wt% %, About 1% to about 20%, about 1% to about 10%, about 1% to about 5%, about 5% to about 50%, about 5% to about 40% %, About 5% to about 30%, about 5% to about 20%, or about 5% to about 10% by weight. In some embodiments, 100% of the area of the outer surface of the silica particles is coated with cationic species. In other embodiments, about 50%, about 60%, about 70%, about 80%, about 90% or about 99% of the area of the outer surface of the silica particles is coated with the cationic species. In some embodiments, the outer surface of the silica particles is uniformly coated with cationic species (eg, the amount of cationic species that coats the particles is equally distributed over the outer surface of the particles). In some embodiments, the particles are coated with two or more types of cationic species, for example, the coated silica particles containing the metal ion (for example, Al ^{3 +)} and PDADMAC binding non-covalently to the surface of the particles.

The core of the particles may comprise additional materials other than silicon dioxide. The core of the particles and the outer surface of the particles may contain metal salts, metal oxides, metal hydroxides, silicon, carbon, silicon carbide, silicon halides or similar materials. In some embodiments, the particles contain about 85 wt% to about 99 wt% silicon dioxide. In some embodiments, the particles may also contain CaO, MgO, Na ₂ O, K ₂ O, Al ₂ O ₃ , Fe ₂ O ₃ , SiC, Si, C, SiF ₄ or SiCl ₄ and any combination thereof. Can be. In some embodiments, the combined amount of these materials in the coated particles ranges from about 1 wt% to about 15 wt%. In some embodiments, the combined amount of materials other than silicon dioxide in the coated silica particles ranges from about 1 wt% to about 5 wt%.

In some embodiments, the coated silica particles of the present disclosure are fine particles. In such embodiments, the size (eg, diameter) of the fine particles ranges from about 1 micrometer (μm) to about 1000 μm, about 1 μm to about 800 μm, about 1 μm to about 500 μm, about 1 μm to about 250 μm, about 1 μm to about 100 μm, or about 10 μm to about 50 μm. In some embodiments, the coated silica particles are nanoparticles. In such embodiments, the size (eg, diameter) of the nanoparticles is about 1 nm to about 1000 nm, about 1 nm to about 900 nm, about 1 nm to about 800 nm, about 1 nm to about 700 nm, about 1 nm to about 600 nm, about 1 nm to about 500 nm, about 1 nm to about 400 nm, about 1 nm to about 300 nm, about 1 nm to about 200 nm, about 1 nm to about 150 nm, about 1 nm To about 100 nm, about 1 nm to about 50 nm, about 5 nm to about 100 nm, about 5 nm to about 50 nm, about 5 nm to about 25 nm, about 5 nm to about 20 nm, or about 5 nm to About 17 nm. In some embodiments, the coated silica particles form a composition, and the median size of the particles in the composition is about 1 nm, about 5 nm, about 10 nm, about 20 nm, about 25 nm, about 50 nm, about 100 nm, Or about 150 nm. The median size of the particles may be based on volume average criteria, which is the size of the particles at 50% in the cumulative particle distribution. In any of the embodiments mentioned above, the size of the particles can be the actual diameter of the particles or the diameter of the equivalent spherical particles.

In some embodiments, the coated silica particles are spherical, cylindrical, hemispherical, rod or cone. In some embodiments, the particles are spherical or substantially spherical.

In some embodiments, coated silica particles present in a population, for example in a composition, may be monodisperse, meaning that the particles in the population have substantially the same shape or size. For example, a particle has a larger diameter such that about 5% or less or about 10% or less of the particle is greater than about 10% above the average diameter of the particle, and in some cases about 8%, about 5%, about 3 The percent, about 1%, about 0.3%, about 0.1%, about 0.03%, or about 0.01% or less may have a distribution that has a larger diameter to a level greater than about 10% above the average diameter of the particles. In some embodiments, up to 25% of the diameter of the particles varies from the mean particle diameter by more than 150%, 100%, 75%, 50%, 25%, 20%, 10%, or 5% of the mean particle diameter. . It is often desirable to create a relatively uniform population of particles in one or more aspects of size, shape, and composition so that most particles have similar properties. For example, at least 80%, at least 90% or at least 95% of the coated silica particles can have a diameter or maximum dimension that falls within 5%, 10% or 20% of the average diameter or maximum dimension of the population. In some embodiments, the population of coated silica particles is uniform with respect to size, shape, mass and composition.

In some embodiments, the present application provides coated silica particles made by any of the methods described later herein.

In some embodiments, the silica particles are not pretreated before coating with cationic species. For example, the silica particles are not treated with stabilizers before the silica particles are coated with cationic species. In some embodiments, the silica particles are not treated with a neutral hydrophilic polymer before the silica particles are coated with cationic species. In some embodiments, the silica particles are coated with sodium citrate, gallic acid, sodium dodecyl sulfate, cetyl trimethyl ammonium bromide (CTAB), gelatin, D-sorbitol, polyvinylpyrrolidone (PVP) before the silica particles are coated with cationic species. , Polyvinyl alcohol (PVA), poly (methylvinylether) (PMVE), or a combination thereof. In some embodiments, the silica particles are not coated with polyvinylpyrrolidone (PVP).

In some embodiments, the silica particles are not porous (eg mesoporous). In some embodiments, the silica particles are porous (eg, mesoporous with pores having a diameter of about 1 nm to about 50 nm).

Cationic species

In some embodiments, the cationic species comprises a cationic polymer. In some embodiments, the cationic polymer comprises at least one positively charged center (eg, atom or group of atoms), such as an ammonium cation, phosphonium cation or guanidinium cation. In some embodiments, the cationic polymer includes cationic centers charged in an amount of about 10 to about 2,000. In some embodiments, the cationic polymer comprises about 100 to about 1,000, about 100 to about 800, or about 100 to about 400 cationic centers. In some embodiments, the cationic polymer has about 500 Da to about 2,000,000 Da, about 1,000 Da to about 1,500,000 Da, about 1,000 Da to about 1,000,000 Da, about 1,000 Da to about 800,000 Da, about 1,000 Da to about 500,000 Da, about Volume averages of 1,500 Da to about 500,000 Da, about 50,000 Da to about 400,000 Da, about 50,000 Da to about 350,000 Da, about 1,500 Da to about 100,000 Da, about 100,000 Da to about 350,000 Da, or about 200,000 Da to about 350,000 Da Or a number average molecular weight. In some embodiments, the cationic polymer is water soluble, for example, the water solubility of the cationic polymer is from about 5 wt% to about 80 wt%, about 10 wt% to about 70 wt%, about 10 wt% to about 60 wt% %, About 10% to about 50%, or about 20% to about 40% by weight. In some embodiments, the water solubility of the cationic polymer is at least about 10% by weight.

In some embodiments, the cationic species is a quaternary ammonium cationic polymer. In some embodiments, the quaternary ammonium cationic polymer is PDADMAC. In some embodiments, PDADMAC has the following structural repeat units:

In some embodiments, the PDADMAC has the following structure:

Where n is an integer from 10 to 5,000. Monomer diallyl dimethyl ammonium chloride (DADMAC) is formed by reacting two equivalents of allyl chloride with dimethylamine. PDADMAC is then synthesized by radical polymerization of DADMAC using a catalyst / activator of the polymerization reaction (eg, an organic peroxide such as t -BuOOH). The polymerization reaction can be carried out at a high temperature (eg, 50 to 75 degrees Celsius), for example, as shown in Scheme 1 below.

Scheme 1

Referring to Scheme 1, two polymer structural repeat units, i.e., N-substituted piperidine structures or N-substituted pyrrolidine structures, are possible when polymerizing DADMAC, and pyrrolidine structures are advantageous for the polymerization reaction. In some embodiments, PDADMAC does not include piperidine containing repeat units. In other embodiments, PDADMACs include both pyrrolidine-containing and piperidine-containing repeat units.

In some embodiments, the cationic polymer is an air of DADMAC and acrylic acid, acrylamide, acrylonitrile, methacrylic acid, methacrylamide, cellulose or cellulose derivative (eg hydroxyethyl cellulose) or any combination thereof. (Eg, the cationic polymer is co-DADMAC). In some embodiments, the cationic polymer is a polyquaternium polymer. In some embodiments, the cationic polymer is selected from the group consisting of: ethanol, 2,2 ', 2 "-nitrilotris-, 1,4-dichloro-2-butene and N, N, N', N Polymer with '-tetramethyl-2-butene-1,4-diamine (polyquaternium-1), poly [bis (2-chloroethyl) ether-alt-1,3-bis [3- (dimethylamino) Propyl] urea] (polyquaternium-2), diallyldimethylammonium chloride (DADMAC) -hydroxyethyl cellulose copolymer (polyquaternium-4), a copolymer of acrylamide and quaternized dimethylammoniumethyl methacrylate (Polyquaternium-5), copolymers of acrylamide and diallyldimethylammonium chloride (P (AAm-co-DADMAC) or polyquaternium-7), methyl and stearic acid of methacrylic acid quaternized with dimethylsulfate Copolymer of aryl dimethylaminoethyl ester (polyquaternium-8), N, N- (dimethylamino) ethyl of methacrylic acid quaternized with bromethane A homopolymer of steter (polyquaternium-9), a copolymer of quaternized hydroxyethyl cellulose (polyquaternium-10), vinylpyrrolidone and quaternized dimethylaminoethyl methacrylate (polyquaternium- 11), ethyl methacrylate / abiethyl methacrylate / diethylaminoethyl methacrylate copolymer (polyquaternium-12) quaternized with dimethyl sulfate, ethyl methacrylate quaternized with dimethyl sulfate / Oleyl methacrylate / diethylaminoethyl methacrylate copolymer (polyquaternium-13), trimethylaminoethyl methacrylate homopolymer (polyquaternium-14), acrylamide-dimethylaminoethyl methacrylate methyl chloride Copolymer (polyquaternium-15), copolymer of vinylpyrrolidone and quaternized vinylimidazole (polyquaternium-16), adipic acid, dimethylaminopropylamine and dichloroethylether copolymer (polyquater Nium-17), azelanic acid, dimethylaminopropylamine and dichloroethylether copolymer (polyquaternium-18), a copolymer of polyvinyl alcohol and 2,3-epoxypropylamine (polyquaternium-19), polyvinyl Reaction with copolymer of octadecyl ether and 2,3-epoxypropylamine (polyquaternium-20), copolymer of acrylic acid and diallyldimethylammonium chloride (polyquaternium-22), lauryl dimethyl ammonium substituted epoxide Quaternary ammonium salts of one hydroxyethyl cellulose (polyquaternium-24), block copolymers of polyquaternium-2 and polyquaternium-17 (polyquaternium-27), vinylpyrrolidone and methacrylamido Copolymer of propyl trimethylammonium (polyquaternium-28), chitosan (polyquaternium-29), modified with propylene oxide and quaternized with epichlorohydrin, ethaneaminium, N- (carboxymethyl) -N, N -Dimethyl-2-[(2-methyl-1-oxo-2-propen-1-yl) oxy]-, internal salt, methyl Polymer with 2-methyl-2-propenoate (polyquaternium-30), N, N-dimethylaminopropyl-N-acrylamidine, quaternized with diethylsulfate bonded to a block of polyacrylonitrile (Polyquaternium-31), poly (acrylamide 2-methacryloxyethyltrimethyl ammonium chloride) (polyquaternium-32), a copolymer of trimethylaminoethylacrylate salt and acrylamide (polyquaternium-33), Copolymers of 1,3-dibromopropane and N, N-diethyl-N ', N'-dimethyl-1,3-propanediamine (polyquaternium-34), methacryloyloxyethyltrimethylammonium and Metosulfate (polyquaternium-35) of a copolymer of methacryloyloxyethyldimethylacetylammonium, a copolymer of N, N-dimethylaminoethyl methacrylate and butyl methacrylate quaternized with dimethyl sulfate ( Polyquaternium-36), poly (2-methacryloxyethyltrimethylammonium chloride (polyquaternium-37), Tripolymers of krylic acid, acrylamide and diallyldimethylammonium chloride (polyquaternium-39), poly [oxyethylene (dimethylimino) ethylene (dimethylimino) ethylene dichloride] (polyquaternium-42), acryl Copolymer of amide, acrylamidopropyltrimonium chloride, 2-amidopropylacrylamide sulfonate and dimethylaminopropylamine (polyquaternium-43), 3-methyl-1-vinylimidazolium methyl sulfate-N Vinylpyrrolidone copolymer (polyquaternium-44), copolymer of (N-methyl-N-ethoxyglycine) methacrylate quaternized with dimethyl sulfate and N, N-dimethylaminoethyl methacrylate (Polyquaternium-45), terpolymers of vinylcaprolactam, vinylpyrrolidone and quaternized vinylimidazole (polyquaternium-46), acrylic acid, methacrylamidopropyl trimethylammonium chloride, methyl acrylate Terpolymer (polyquaternium-47), and Combinations of these.

In some embodiments, the cationic polymer is poly (2-hydroxypropyl-1-N-dimethylammonium chloride) (CAS Registry No. 25988-97-0). In some aspects of these embodiments, the cationic polymer has the following structural repeat units:

In some embodiments, the cationic polymer is poly (2-dimethylamino) ethyl methacrylate) methyl chloride quaternary salt (MADQUAT, CAS Registry No. 26161-33-1). In some aspects of these embodiments, the cationic polymer has the following structural repeat units:

In some embodiments, the cationic polymer is optionally quaternized poly (N-dimethylaminopropyl) -methacrylamide (eg, methyl chloride quaternary salt). In some aspects of these embodiments, the cationic polymer has the following structural repeat units:

In some embodiments, the cationic polymer is poly (2-hydroxypropyl-1-1-N-dimethylammoniumchloride), poly [N- (dimethylaminomethyl)]-acrylamide, or poly (2-vinylimimide). Zolinium bisulfate).

In some embodiments, cationic species typically comprise a positively charged compound having a molecular weight of about 2,000 Da or less. In some aspects of these embodiments, the volume average or number average molecular weight of the positively charged cationic compound is about 50 Da to about 2,000 Da, about 100 Da to about 1,800 Da, about 150 Da to about 1,600 Da, about 100 Da To about 1,400 Da, about 150 Da to about 1,200 Da, about 100 Da to about 1,000 Da, about 150 Da to about 800 Da, about 150 Da to about 600 Da, about 150 Da to about 500 Da, or about 150 Da to In the range of about 400 Da. In some embodiments, the cationic compound comprises at least one positively charged center (eg, a positively charged atom or group of atoms), such as an ammonium cation, phosphonium cation or guanidinium cation . In some embodiments, the cationic compound includes cationic centers charged in amounts of 1-20. For example, cationic compounds include atoms or groups of atoms charged in amounts of 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10.

In some embodiments, the positively charged compound comprises a quaternary ammonium compound. In some embodiments, the quaternary ammonium compound is quaternium (eg, a compound comprising a single quaternary ammonium center). For example, quaternium compounds can be selected from hexamethylenetetraamine chloroallyl chloride (CAS reg. No. 4080-31-3) (quaternium-15) or dimethyldioctadecylammonium chloride (CAS reg. No. 61789-80-8) (quarter Nium-18).

In some embodiments, the quaternary ammonium compound comprises more than one quaternary ammonium center (eg, 2, 3, 4 or more quaternary ammonium cations in the compound). In some embodiments, the quaternary ammonium compound has 1,2-ethanedianium, N, N'-bis [2- [bis (2-hydroxyethyl) methylammonium] ethyl] -N, having the chemical structure , N'-bis (2-hydroxyethyl) -N, N'-dimethyl-, tetrachloride (CAS Registry No. 138879-94-4) (Clay Master ™ 5C):

In some embodiments, the quaternary ammonium compound is selected from the group consisting of:

,

,

,

,

, 및

, And

.

.

In some embodiments, the cationic species is a metal cation. In some embodiments, the metal cation comprises two or more oxidation states, for example the metal cation is M ²⁺ , M ³⁺ , M ⁴⁺ , M ⁵⁺ or M ⁶⁺ . In some examples, the metal cation is iron (Fe), aluminum (Al), calcium (Ca), magnesium (Mg), zinc (Zn), titanium (Ti), chromium (Cr), manganese (Mn), cobalt (Co) ), Vanadium (V), nickel (Ni), copper (Cu), silver (Ag), and lead (Pb).

In some embodiments, the metal cation is Fe ^{2 +} , Fe ^{3 +} , Al ^{3 +} , Ca ^{2 +} , Mg ^{2 +} , Zn ^{2 +} , Cr ^{2 +} , Cr ^{3 +} , Cr ⁴⁺ , Cr ^{5 +} , Cr ⁶ Metals selected from the group consisting of ⁺ , V ⁴⁺ , V ⁵⁺ and Ti ^{4 +} . In some embodiments, the metal cations are Fe ^{+ 3,} or Al ^{+ 3.} In some embodiments, the metal cation forms a salt thereof, or solvate or hydrate. For example, the metal salt may be FeCl ₂ , FeCl ₃ , FeF ₃ , FeSO ₄ , Fe ₂ (SO ₄ ) ₃ , K ₄ Fe (CN) ₆ , Fe ₄ (P ₂ O ₇ ) ₃ , FePO ₄ , Fe (ClO ₄ ) ₂ , Fe ₂ (C ₂ O ₄ ) ₃ , Fe (NO ₃ ) ₃ , FeBr ₃ , AlBr ₃ , AlCl ₃ , AlF ₃ , Al (PO ₃ ) ₃ , Al (NO ₃ ) ₃ , AlNH ₄ ( SO ₄ ) ₂ , Al ₂ (SO ₄ ) ₃ , KAl (SO ₄ ) ₂ (alum), CaBr ₂ , CaCl ₂ , Ca (N0 ₃ ) ₂ , MgCl ₂ and MgBr ₂ , and solvates or hydrates thereof It may be selected from the group. In other embodiments, the metal cation forms a metal oxide or metal hydroxide, or solvate or hydrate thereof. For example, the metal oxide or hydroxide may be Fe ₂ O ₃ , FeO, Fe ₂ NiO ₄ , Fe ₃ O ₄ , Fe (OH) ₂ , Fe (OH) ₃ , FeOOH, aluminosilicate (SiO ₂ ) _x (Al ₂ O ₃ ) _y , Al ₂ O ₃ , Al ₂ O ₃ / ZnO, ZnO, CaC, Mg (OH) ₂ and Al (OH) ₃ , and solvates or hydrates thereof. In some embodiments, the metal cation, or compound comprising the metal cation (eg, metal salt, oxide or hydroxide) is water soluble. For example, in some embodiments, the water solubility of the compound can range from about 5% to about 75% by weight of the aqueous solution (eg, the water solubility of the compound is about 10% by weight, about 15% by weight of the aqueous solution). %, About 20% by weight, or about 30% by weight).

A composition comprising the coated silica particles of the present disclosure

The present disclosure also provides compositions comprising coated silica particles as described earlier in this specification. In some embodiments, the present disclosure provides a composition comprising a particulate material comprising coated silica particles. For example, the particulate material may include silica not coated with cationic species and at least one silica particle coated with cationic species. In another example, the composition contains a plurality of coated silica particles. In some embodiments, the composition comprises a particulate material comprising only silica particles coated with cationic species and does not include any uncoated silica. In some embodiments, the composition comprises silica particles coated with at least about 25%, about 35%, about 50%, about 60%, about 75%, about 90% by weight, or about 99% by weight of cationic species, The remaining amount of particulate material is uncoated silica particles. In another embodiment, the composition comprises a particulate material comprising 100% by weight of a plurality of coated silica particles.

In some embodiments, the amount of particulate material in the composition is about 1% to about 90%, about 1% to about 80%, about 1% to about 70%, about 1% to about 60% by weight. , About 1 wt% to about 50 wt%, about 1 wt% to about 40 wt%, about 1 wt% to about 35 wt%, about 1 wt% to about 25 wt%, about 1 wt% to about 20 wt% Or from about 1% to about 15% by weight. In some embodiments, the amount of particulate material in the composition is about 5% to about 50%, about 10% to about 50%, about 5% to about 40%, about 10% to about 35% by weight. , About 5% to about 35%, about 10% to about 25%, about 5% to about 15%, or about 15% to about 35% by weight. In some embodiments, the amount of particulate material in the composition is about 5%, about 7.5%, about 10%, about 12.5%, about 15%, about 20%, about 25%, about 30% by weight. , About 35%, about 40%, about 50%, about 60%, or about 75% by weight.

In some embodiments, the composition comprises a solvent, such as an aqueous solvent. In some embodiments, the aqueous solvent comprises water. In some embodiments, the aqueous solvent also includes other solvents than water, such as alcohols such as methanol, ethanol, ethylene glycol, propylene glycol, polyethylene glycol, polypropylene glycol, glycerin or mixtures thereof. In some embodiments, the aqueous solvent comprises water in an amount of about 40%, about 50%, about 60%, about 70%, about 80%, or about 90% or more, with the remaining amount being It is a solvent other than water. In some embodiments, water is the only solvent in the composition.

In some embodiments, the composition comprises about 10% to about 90%, about 10% to about 80%, about 10% to about 70%, about 10% to about 60%, about 10% to about solvent, by weight or volume About 50%, about 50% to about 90%, or about 50% to about 75%. In some aspects of these embodiments, the solvent is water.

In some embodiments, the pH of the composition is about 7 to about 12, about 7.5 to about 12, about 8 to about 12, about 8 to about 11, about 9 to about 12, or about 9 to 11. The pH of the composition is sufficient to, for example, ensure stability of the composition, prevent aggregation of particulate matter in the composition, and prevent premature curing of the composition. In some embodiments, the viscosity of the composition is from about 1 centipoise (cP) to about 20 cP, about 1 cP to about 18 cP, about 1 cP to about 15 cP, about 1 cP to about 12 cP, about 1 cP to about 10 cP, about 1 cP to about 8 cP, about 1 cP to about 5 cP, about 5 cP to about 20 cP, about 5 cP to about 15 cP, about 5 cP to about 10 cP or about 8 cP to about 10 cP to be. The viscosity of the composition is such as to ensure the flowability of the composition so that it can be placed at a convenient and appropriate time in the target zone of the underground strata, for example using conventional oil well equipment (eg, using coil tubing equipment). Suffice.

In some embodiments, the particulate silica material and solvent are the only components in the composition. In other embodiments, the composition further comprises an activator. In some embodiments, a composition of the present disclosure is curable, that is, the composition forms a hard gel after a period of time (eg, the composition is a delayed gelling composition). In some embodiments, the composition is considered a hard gel when it cannot flow. In some embodiments, the composition comprises about 1 hour, about 2 hours, about 3 hours, about 4 hours, about 5 hours, about 6 hours, about 8 hours, about 10 hours or about 12 hours or more after the composition is formed. After time a hard gel is formed. In some embodiments, the composition can form a hard gel without activator. In other embodiments, the composition forms a hard gel due to the presence of an activator in the composition. The formation of hard gels is possible because the silica particles (eg coated silica particles) aggregate to form a solidified material. In some embodiments, the curable composition forms a hard gel when the pH of the composition changes to a pH of less than 7, for example. In some examples, the composition forms a hard gel at a pH of about 7, about 6.5, about 6, about 5.5, about 5, or about 4. In the acidic pH range, the silica particles aggregate to form a solidified material. In some embodiments, the curable composition forms a hard gel at ambient temperature. In some embodiments, the curable composition forms a hard gel at a temperature below ambient temperature (eg, when the underground strata temperature is below ambient temperature). In some embodiments, the curable composition forms a hard gel at high temperature (eg, when the underground strata temperature is above ambient temperature). In some aspects of these embodiments, the curable composition can be from about 50 degrees Fahrenheit to about 500 degrees Fahrenheit, about 50 degrees F to about 450 degrees F, about 50 degrees F to about 400 degrees F, about 50 degrees F to about 350 degrees F, about 75 degrees Fahrenheit. Freeze at temperatures between about 0 ° F. and about 500 ° F., between about 75 ° F. and about 350 ° F., between about 75 ° F. and about 250 ° F., between about 150 ° F. and about 500 ° F., between about 150 ° F. and about 350 ° F. Form a hardened hard gel.

In some embodiments, the composition comprises an activator. Suitable examples of activators include alkali silicates such as sodium silicate (Na-silicate) or potassium silicate (K-silicate). Na-silicate as used in this disclosure refers to compounds having the formula (Na ₂ SiO ₂ ) _n O. In some embodiments, the Na-silicate is sodium silicate (Na ₂ SiO ₃ ) or polymeric silicate compound of formula (Na ₂ SiO ₂ ) _n O. Similarly, K-silicate used in the present disclosure refers to a compound having the formula (K ₂ SiO ₂ ) _n O. In some embodiments, K-silicate is a potassium silicate (K ₂ SiO ₃ ) or polymeric silicate compound of formula (K ₂ SiO ₂ ) _n O. In some embodiments, the activator promotes the interaction between the cationic coating of the silica particles and the sand particles.

The amount of activator in the composition is sufficient to, for example, activate the coated silica in the composition and increase the rate of sand solidification by the coated silica in the composition. In some embodiments, the activator is activated at increased temperatures, such as about 100 ° C to about 200 ° C. In some embodiments, the activator promotes curing of the composition. In some embodiments, the composition comprises about 0.1% to about 10%, about 0.1% to about 8%, about 0.1% to about 5%, about 0.25% to about 10% by weight of activator, About 0.25% to about 5%, about 0.25% to about 4%, about 0.5% to about 10%, about 0.5% to about 7.5%, about 0.5% to about 5%, About 1% to about 10%, about 1% to about 7.5%, about 2% to about 5%, or about 1% to about 5% by weight. In some embodiments, the composition has about 0.1%, about 0.25%, about 0.5%, about 1%, about 2%, about 3%, about 4%, about 5%, about 7.5% %, Or about 10% by weight of activator.

In some embodiments, the activator is a pH adjuster. For example, pH adjusting agents are chemical compounds that can reduce the pH of a composition. In one example, the pH adjusting agent is an ester compound. The ester compound may be represented by the formula RC (= O) 0-R ', wherein R and R' are each independently optionally substituted C _1-10 alkyl (eg, methyl, ethyl, propyl, iso Propyl, butyl, pentyl, hexyl, etc.), or optionally substituted C _6-10 aryl (eg phenyl), C _3-7 cycloalkyl (eg cyclohexyl) or C _3-7 heterocycloalkyl (E.g., tetrahydrofuranyl). Optional substituents include OH, NH ₂ , SH, CN, halo and similar groups. In some embodiments, the ester compound is an ester of an organic acid selected from the group consisting of formic acid, isobutyric acid, acetic acid, lactic acid, succinic acid, maleic acid, malic acid, and combinations thereof. In some embodiments, the ester compound is ethyl formate, methyl formate, triethyl orthoformate, trimethyl orthoformate, diethylene glycol diformate, ethylene glycol diformate, dipropylene glycol diformate, ethyl lactate , Methyl lactate and combinations thereof. In some embodiments, the ester compound is a polymeric material (eg, polylactide resin). In some embodiments, the ester compound is hydrolyzed in the composition after a period of time (eg, about 3 hours) after the composition is formed to reduce the pH of the composition by producing a corresponding acid (eg, formic acid or lactic acid). And activate the curing of the composition. In some embodiments, hydrolysis of the ester compound reduces the pH of the composition to about 6, about 5 or about 4. In some embodiments, the ester compound in the composition is hydrolyzed at underground strata temperatures. In some embodiments, the ester compound is about 50 ° F. to about 500 ° F., about 50 ° F. to about 350 ° F., about 50 ° F. to about 250 ° F., about 75 ° F. to about 500 ° F., about 75 ° F. to about 350 ° F., about 75 Hydrolyze at a temperature between F and about 250 F, about 150 and about 500 F, or about 150 and about 250 F. In some embodiments, the composition comprises about 0.1% to about 10%, about 0.1% to about 5%, about 0.25% to about 10%, about 0.25% to about 4% of the ester compound by weight of the composition. % Or about 1% to about 5% by weight.

In some embodiments, the composition comprises an activator comprising an ionic strength modifier. In some embodiments, the ionic strength modifier is an inorganic electrolyte, such as an alkali metal or alkaline earth metal salt. In some aspects of these embodiments, the metal salt is selected from the group consisting of KCl, NaCl, NBr, NaBr, CaCl ₂ , CaBr ₂ , LiCl, KNO ₃ , Na ₂ (SO ₄ ) _3, and combinations thereof. In some embodiments, the ionic strength modifier facilitates agglomeration of the silica particles to facilitate curing and solidification of the composition. In some embodiments, the composition comprises an ionic strength modifier from about 0.1% to about 10%, about 0.1% to about 5%, about 0.25% to about 10%, about 0.25% to about 5 of the composition. Wt%, or from about 1 wt% to about 5 wt%.

In some embodiments, the composition comprises any amount of pH regulator and ionic strength regulator disclosed earlier in this specification. In some embodiments, the present application provides a composition comprising coated silica particles made by any of the methods described later herein.

Preparation of Coated Silica Particles and Compositions

The present application also provides a method of making the coated silica particles described earlier in the present specification, comprising: (i) obtaining a colloidal dispersion comprising solid silica particles and a solvent; (ii) obtaining a cationic species; And (iii) combining the colloidal dispersion of step (i) with the cationic species of step (ii) to obtain coated silica particles. In some embodiments, the colloidal dispersion comprises a dispersed phase and a continuous phase, the dispersed phase comprises solid silica particles (eg, a plurality of solid silica particles), and the continuous phase comprises a solvent (eg water).

Solid silica particles in the dispersion comprise a core and an outer surface. The core of the silica particles comprises SiO ₂ and optionally other materials (eg, Al ₂ O ₃ , Si, C, SiC, SiCl ₄ as described earlier for the coated silica particles). The outer surface of the silica particles includes silanol groups and silyloxy anions (see, eg, FIGS. 2A and 2B). In some embodiments, the outer surface of the solid silica particles is negatively charged. For example, silanol dipoles and silyloxy anions on the outer surface of the silica particles contribute to the net negative charge on the outer surface. The colloidal dispersion comprises particulate silica material (eg, a plurality of solid silica particles). In some embodiments, the silica particles are monodisperse (eg, have a uniform size, shape, and composition as described earlier in the specification for the coated silica particles). In some embodiments, the particulate silica material is the only component of the dispersion phase of the dispersion. In other embodiments, the dispersed phase of the dispersion comprises a material other than particulate silica (eg, sand, clay or cement). The solvent in the continuous phase of the dispersion may include solvents other than water (eg, alcohols or other solvents as described earlier in this specification). In some embodiments, water is the only solvent in the dispersion. In some embodiments, the particulate silica in the dispersion is about 10 square meters / gram (m ² / g) to about 2,000 m ² / g, about 20 m ² / g to about 1,500 m ² / g, or about 30 m ² / g It has a surface area per unit mass of dispersion in the range from about 1,000 m ² / g. In some embodiments, the solid silica particles in the dispersion are fine particles or nano particles (eg, as described earlier for coated silica particles). In some embodiments, the solid silica particles have about 1 nm to about 1,000 nm, about 1 nm to about 500 nm, about 1 nm to about 150 nm, about 1 nm to about 50 nm, about 4 nm to about 50 nm, or Nanoparticles having a size (eg, diameter) of about 5 nm to about 17 nm. In some embodiments, the amount of particulate silica material in the dispersion is about 1% to about 90%, about 5% to about 75%, about 10% to about 75%, about 5% to about 50% by weight. %, Or about 10% to about 50% by weight. In some embodiments, the amount of particulate silica material in the dispersion is about 5%, about 10%, about 15%, about 20%, about 35%, or about 50% by weight. ChemBinder® 50 from Akzo Nobel is a non-limiting example of a colloidal silica dispersion.

In some embodiments, the cationic species may be obtained as a solution in a solvent, for example, a PDADMAC solution in water or a mixture of water and alcohol as described earlier in this specification. In some embodiments, cationic species can be obtained as a mixture (eg, a solution) in water. In some embodiments, the concentration of cationic species in the solution is about 5% to about 75%, about 10% to about 75%, about 5% to about 50%, or about 10% to about 50% by weight %to be. In some embodiments, the concentration of cationic species in the mixture with the solvent is about 5%, about 10%, about 15%, about 20%, about 35%, or about 50% by weight. In some embodiments, the amount of cationic species obtained in step (ii) is about 0.01 wt% to about 5 wt%, about 0.05 wt% to about 5 wt%, about 0.1 relative to the amount of colloidal dispersion comprising solid particulate silica Wt% to about 5 wt%, about 0.25 wt% to about 5 wt%, about 0.5 wt% to about 5 wt%, about 1 wt% to about 5 wt%, about 0.1 wt% to about 4 wt%, or about And 0.1 wt% to about 2 wt%.

In some embodiments, the combination comprises adding the cationic species obtained in step (ii) to the colloidal dispersion obtained in step (i). In other embodiments, the combination comprises adding the colloidal dispersion obtained in step (i) to the cationic species obtained in step (ii). In some embodiments, the combination comprises the uniform distribution of cationic species in the colloidal dispersion. Referring to FIG. 3, after combining a cationic species (eg, PDADMAC) and a colloidal dispersion, the cationic species may be covalently bound to, for example, silanol dipoles and silyloxy anions on the outer surface of the silica particles. Coating the solid silica particles forms coated silica particles as described earlier in this specification. The positively charged cation center of the cationic species facilitates the binding due to the electrostatic attraction between the positively charged atoms and the negatively charged silanol groups and silyloxy anions on the outer surface of the silica particles. In some embodiments, the combination comprises continuously stirring the mixture of the silica dispersion and the cationic species (eg, the reaction mixture). Stirring can include stirring, swirling or shaking, or any combination thereof. Stirring of the reaction mixture can be performed using any conventional equipment and protocols known in the art, for example using conventional blender apparatus. Stirring of the reaction mixture typically takes a sufficient time (eg, from about 1 minute to about 30 minutes, 1 minute to about 20 minutes, about) to produce coated silica particles as described earlier in this specification. 1 minute to about 15 minutes, about 1 minute to about 10 minutes, or about 1 minute to about 5 minutes).

In some embodiments, the method comprises obtaining an activator. In some embodiments, the activator can be obtained as a solution in a solvent, such as a solution of Na-silicate or K-silicate in water or a mixture of water and alcohol. In some embodiments, the method comprises combining the activator with a colloidal dispersion of solid silica particles obtained in step (i). In some embodiments, the method comprises combining the activator with the cationic species obtained in step (ii). In some embodiments, the method comprises combining the activator with the coated silica particles obtained in step (iii).

In some embodiments, the method removes a solvent (eg, water) from the reaction mixture to obtain solid silica particles (eg, powdered particulate material comprising coated particles) coated with cationic species. It further includes. The solvent may be removed by any conventional technique, such as rotary evaporation or lyophilization.

In some embodiments, the present application provides a method of making a composition (eg, a curable delayed gelling composition) comprising the coated silica particles described earlier. In some embodiments, a method of making a composition comprises solid silica particles (eg, particulate material comprising a plurality of coated particles) and a solvent (eg, water or a water / alcohol mixture) coated with cationic species. Combining. In other embodiments, curable delayed gelling compositions comprising coated particles can be prepared using any of the methods described earlier to produce coated silica particles. In some aspects of these embodiments, the method of preparing the composition comprises (i) obtaining a colloidal dispersion comprising solid silica particles and a solvent; (ii) obtaining a cationic species; And (iii) combining the colloidal dispersion of step (i) with the cationic species of step (ii) to include coated silica particles (eg, coated silica particles or particulate material comprising a plurality of coated particles). Obtaining a curable composition. Non-limiting embodiments of this method are described earlier in this specification for methods of making coated silica particles. In some embodiments, a method of making a curable composition includes adding at least one activator to the composition / dispersion / reaction mixture. For example, any one of the activators described earlier in this specification can be added to the composition in any amount described above. The activator can be added to the composition / dispersion / reaction mixture in solution form. For example, if the activator is an ionic strength modifier such as NaCl, the concentration of the ionic strength modifier in the solution may range from about 1 weight to volume% (% w / v) to about 30% w / v, about 5% w / v to About 25% w / v, or about 5% w / v to about 15% w / v. In some embodiments, the method includes adding at least two activators (eg, ionic strength regulators and pH regulators) to the composition. The components of the composition can be mixed at the site of use (eg near the oil well) using conventional crushed blender units.

Underground strata To solidify  Of coated particles and compositions for use

In some embodiments, the present application provides a method of solidifying a soft underground strata formation comprising contacting the soft underground strata with a composition comprising coated silica particles as described earlier in this specification. In some embodiments, the contact provides solidified particles of underground particles. The soft, unsolidified underground strata contain loosely solidified particles that can be transported away from the strata as the recoverable fluid flows through the strata. The strata can lose their structural support, erode and collapse, resulting in damage to the oil wells and equipment. Loose underground particles may include grains of sand, clay or rock such as sandstone, gravel, limestone, quartz, zeolite, silt or shale, or any combination thereof. Most often, the soft underground strata have loosely grained sand grains. Contacting the unconsolidated sand particles of the strata with the curable delayed gelling composition of the present invention may solidify the sand grains together at the point of contact. This creates a powerful solidified matrix that solidifies the strata.

The surface of unsolidified sand grains (or particles) has a net negative charge. Positively charged silica particles coated with cationic species can self-associate on the unsolidified layered sand particles due to electrostatic attraction to form a layer of solidified material. Referring to FIG. 4, when the composition is cured in the stratification layer 1 at the positively charged negatively charged interface 3, a thin layer of hard gel containing solidified silica nanoparticles 4 is unsolidified sand particles 2. ) Is formed around. This hard gel can solidify the sand grains together while maintaining the desired porosity through the treated solidified material, thereby facilitating the production of recoverable fluids such as hydrocarbons. Similar positive charge of the coated silica particles causes repulsion between the coated particles, which maintains the low viscosity of the composition (eg, a viscosity of about 5 cP to about 10 cP), and is transferred to coil tubing, for example. Helps to prevent premature curing of the composition during. The composition is referred to as sand control fill when delivered to the target zone. The charge repulsion between the positively charged individual cationic species and the coated silica particles will prevent any unwanted agglomeration of the coated silica. Similar charge repulsion forces also ensure a single layer coating of the surface of the sand grains in the unsolidified strata. The positively charged silica particles having affinity for the negatively charged sand grains in the strata produce a monolayer coating on the surface of the negatively charged grains of the unsolidified strata.

In some embodiments, the soft strata are penetrated by oil wells. The curable composition can be delivered to a target soft zone that requires treatment using, for example, conventional coiled tubing equipment. In some embodiments, the strata contain a recoverable fluid, such as water or a hydrocarbon such as petroleum or natural gas. In some embodiments, when the soft strata are solidified using the compositions and methods described earlier in this specification, the resulting solidified strata maintain permeability to the fluid recovered. In some embodiments, the method further comprises producing a fluid (eg, oil) from the solidified strata. Production of fluids from oil wells can be accomplished using any conventional equipment generally known in the art.

In some embodiments, the solidified strata comprising solidified particles of underground particles can withstand pressure loads greater than about 700 pound-force (lbf), about 800 lbf, about 900 lbf, about 100 lbf, or about 1,200 lbf. . In some embodiments, the solidified particles of the particles may withstand load pressures ranging from about 700 lbf to about 1000 lbf. In some embodiments, the amount of curable composition delivered to a single sand control fill is about 100 gallons to about 5,000 gallons, about 200 gallons to about 4,500 gallons, about 300 gallons to about 4,000 gallons, about 400 gallons to about 4,000 gallons, or about And may range from 500 gallons to about 3750 gallons. The amount of composition that can be delivered to the target zone is determined by various factors such as the reservoir vertical thickness (eg, about 20 feet to about 150 feet) as determined by a skilled petroleum engineer. In some embodiments, the volume of the curable composition per 20 feet of stratum thickness can be about 500 gallons.

Example

Example  1-Preparation of Coated Silica Nanoparticles

Five milliliters (mL) of Chembinder® 50 (Azo Nobel) colloidal nanosilica was added to the beaker.

Table 1: ChemBinder® 50 Colloidal Products were supplied by Akzo Nobel and had the following characteristics:

In a beaker containing ChemBinder® 50, 0.5 mL of 25% NaCl aqueous solution was introduced with constant stirring. The resulting mixture was mixed for 5 minutes. The nanosilica was then modified using the cationic modifier. The cationic modifier used was Clay Master ™ 5C (Baker Fuse), a complex polyamine salt supplied by Baker Hughes. Clay Master ™ 5C has the chemical name 1,2-ethanediamine, N, N'-bis [2- [bis (2-hydroxyethyl) methylammonium] ethyl] -N, N'-bis (2-hydroxy Polyamine, which is ethyl) -N, N'-dimethyl-, tetrachloride (the formulations commercially available from Baker Hues are 30% to 60% by weight of the active ingredient solution). Nanosilica modification was performed in situ by adding 0.1 mL of Clay Master ™ 5C to a mixture of nanosilica and NaCl (2 v / v% Clay Master ™ 5C relative to the amount of nanosilica and NaCl solution).

Example  2-sand To solidify  Of silica nanoparticles coated for

After stirring the solution prepared in Example 1 for a further 5 minutes, 5 grams of 100 mesh sand was slowly added to the solution under continuous stirring. Because of this, the sand was uniformly coated with cationic modified nanosilica. Nanosilica coated sand was filled into test tubes and cured in a 100 ° C. oven for 24 hours. After 24 hours, the sand was found to be completely solidified as can be seen in FIG. 5. The solidified sand particles had a strength that could withstand an applied pressure load of 700 to 1000 lbf. The compressive strength was determined by a uniaxial stress load frame to measure the unconfined compressive strength (UCS) of solidified sand particles. A cylindrical solidification core of 1 "diameter and 2" length was used. The load is applied to the two flat ends without limiting around the perimeter. The stress at which the solidified core breaks is the UCS of the solidified sand particles (eg, a pressure load between 700 and 1000 lbf).

To confirm that the solidified sand pack was permeable, the same formulation as described earlier was filled into a 10 mL syringe as follows. Loose sand particles were filled into a syringe. The treatment solution was then injected. The treated syringe was kept in an oven at a temperature of 100 ° C. for 24 hours. After the designated time the syringe was removed to obtain a solidified sand pack. 2 mL of 2% NaCl aqueous solution was injected through the solidified sand pack. The sand pack was observed to absorb NaCl solution.

Example  3- Cationic  Nanosilica Gelation

34.5 mL of Levasil® 30-516P Nanosilica (Azo Nobel) was added to the beaker. Levasil® 30-516P nanosilica has a positive surface charge as a whole.

Table 2: Levasil® 30-516P colloidal product was supplied by Akzo Nobel and has the following characteristics:

0.5 ml of 25% aqueous NaCl solution was introduced into this beaker with constant stirring. The resulting mixture was mixed for 5 minutes. Then 5 mL Clay Master ™ 5C was added. The mixture was stirred for 5 minutes. After stirring, 40 g of a 1: 1 mixture of 20:40 mesh and 100 mesh sand was slowly added to the solution under continuous stirring. This produced sand uniformly coated with cationic species. The coated sand was filled into test tubes and placed in an oven at 100 ° C. Test tubes were observed after every hour for curing of the coated sand. If the sand did not flow even after the test tube was flipped, the sand was considered to have completely cured.

In another experiment, 37 mL of Levasil® 30-516P was added to the beaker. 0.5 ml of 25% aqueous NaCl solution was introduced into this beaker with constant stirring. The resulting mixture was mixed for 5 minutes. Then 2.5 mL Clay Master ™ 5C was added. The mixture was stirred for 5 minutes. After stirring, 40 g of a 1: 1 mixture of 20:40 mesh and 100 mesh sand was slowly added to the solution under continuous stirring. The coated sand was filled into test tubes and placed in an oven at 100 ° C. Test tubes were observed after every hour for curing of the coated sand.

For both experiments described above, it was observed that after 24 hours the sand had completely cured.

Example  4-Nanosilica with Alternative Activator Gelation

Na-silicate and K-silicate were used as alternative activators of Levasil® 30-516P nanosilica, respectively. Various formulations using these activators have been studied. The results for cure times using these formulations are shown in Table 3.

The formulations were mixed using the following mixing procedure: Levasil® 30-516P nanosilica was added to the beaker. To this beaker, Na-silicate or K-silicate solution was added dropwise with constant stirring. The resulting mixture was mixed for 5 minutes. Then, Clay Master ™ 5C was added. The mixture was stirred for 5 minutes. After stirring, 40 g of a 1: 1 mixture of 20:40 mesh and 100 mesh sand was slowly added to the solution under continuous stirring. The coated sand was filled into test tubes and placed in an oven at 100 ° C. Test tubes were observed after every hour for curing of the coated sand.

Table 3: Cure Times of Levasil® 30-516P Nanosilica Using Na-Silicate, K-Silicate and Clay Master ™ 5C

To investigate whether the cured sand pack was permeable, the formulation was filled into a 10 mL syringe as described in Example 2. After treating the sand pack with the treatment fluid, the syringe was stored in an oven at a temperature of 100 ° C. for 24 hours. After the designated time, the syringe was removed to obtain a solidified sand pack. A 2% NaCl aqueous solution was continuously injected through the solidified sand pack. It was observed that the NaCl solution passed through the sand pack without any resistance, indicating that the sand pack was permeable.

Specific embodiment

Embodiment 1. Coated silica particles comprising a cationic species non-covalently bound to the outer surface of the particle.

Embodiment 2. The particle of embodiment 1, wherein the particle comprises nanoparticles.

Embodiment 3. The particle of Embodiment 1 or 2, wherein the outer surface of the particle is negatively charged.

Embodiment 4 The particle of embodiment 1 or 2, wherein the outer surface of the particle is positively charged.

Embodiment 5. The particle of any of embodiments 2-4, wherein the nanoparticle comprises a diameter of about 1 nm to about 500 nm.

Embodiment 6. The particle of any of embodiments 2-4, wherein the nanoparticle comprises a diameter of about 1 nm to about 150 nm.

Embodiment 7. The particle of any of embodiments 2-4, wherein the nanoparticle comprises a diameter of about 5 nm to about 50 nm.

Embodiment 8. The particle of any of embodiments 2-4, wherein the nanoparticle comprises a diameter of about 5 nm to about 17 nm.

Embodiment 9. The particle of any of embodiments 1-8, wherein the cationic species comprises a metal cation.

Embodiment 10 The particle of Embodiment 9, wherein the metal cation comprises two or more oxidation states.

Embodiment 11. The particle of Embodiment 9 or Embodiment 10, wherein the metal cation comprises aluminum or iron.

Embodiment 12 The method of any of embodiments 9-11, wherein the metal cation is Al ₂ O ₃ , Al ₂ (S0 ₄ ) ₃ , KAl (S0 ₄ ) ₂ , FeCl ₃ and Fe ₂ (S0 ₄ ) ₃ And a salt or oxide selected from the group consisting of hydrates and solvates thereof.

Embodiment 13. The particle of any of embodiments 1-8, wherein the cationic species comprises a cationic polymer.

Embodiment 14 The compound of embodiment 13, wherein the cationic polymer is selected from the group consisting of poly (2-hydroxypropyl-1-N-dimethylammonium chloride), poly (2-hydroxypropyl-1-1-N-dimethylammonium chloride), Poly [N- (dimethylaminomethyl)]-acrylamide, poly (2-vinylimidazolinium bisulfate), poly (diallyldimethylammonium chloride), poly (N-dimethylaminopropyl) -methacrylamide and these Particles selected from the group consisting of a combination of.

Embodiment 15 The particle of Embodiment 13, wherein the cationic polymer comprises poly (diallyldimethylammoniumchloride).

Embodiment 16 The particle of any of embodiments 13-15, wherein the cationic polymer has a molecular weight of about 1,000 Da to about 1,000,000 Da.

Embodiment 17 The particle of any of Embodiments 13-15, wherein the cationic polymer has a molecular weight of about 1,500 Da to about 500,000 Da.

Embodiment 18 The particle of any of embodiments 13-15, wherein the cationic polymer has a molecular weight of about 1,500 Da to about 100,000 Da.

Embodiment 19 The particle of any of Embodiments 13-18, wherein the cationic polymer is water soluble.

Embodiment 20 The particle of any of embodiments 13-18, wherein the cationic species comprises a quaternary ammonium compound.

Embodiment 21. The compound of embodiment 20, wherein the quaternary ammonium compound is 1,2-ethanedianium, N, N'-bis [2- [bis (2-hydroxyethyl) methylammonio] ethyl] -N, Particles comprising N'-bis (2-hydroxyethyl) -N, N'-dimethyl-, tetrachloride.

Embodiment 22 The particle of any of embodiments 1-21, wherein the amount of cationic species relative to the weight of the silica particle ranges from about 5% to about 20% by weight.

Embodiment 23 The particle of any of embodiments 1-22, wherein the coated particle comprises a net positive charge.

Embodiment 24 The particle of any of embodiments 1-23, wherein the noncovalent bond between the cationic species and the outer surface of the silica particle comprises an electrostatic interaction.

Embodiment 25 The particle of embodiment 24, wherein the electrostatic interaction comprises an attractive force between the negatively charged outer surface of the silica particles and the positively charged cationic species.

Embodiment 26 The particle of embodiment 25, wherein the electrostatic interaction comprises attraction between the silanol groups or silyloxy anions on the outer surface of the silica particles and the positively charged cationic species.

Embodiment 27 A method of making coated silica particles comprising a cationic species non-covalently bound to the outer surface of the silica particles, the method comprising

(i) obtaining a colloidal dispersion comprising solid silica particles in the dispersed phase and a solvent in the continuous phase;

(ii) obtaining a cationic species; And

(iii) combining the colloidal dispersion of step (i) with the cationic species of step (ii) to obtain coated silica particles

That comprises, a method for producing the coated silica particles.

Embodiment 28 The method of embodiment 27, wherein the solid silica particles are nanoparticles.

Embodiment 29 The method of embodiment 28, wherein the nanoparticles comprise a diameter of about 1 nm to about 500 nm.

Embodiment 30 The method of embodiment 28, wherein the nanoparticles comprise a diameter of about 1 nm to about 150 nm.

Embodiment 31 The method of embodiment 28, wherein the nanoparticles comprise a diameter of about 5 nm to about 50 nm.

Embodiment 32 The method of embodiment 28, wherein the nanoparticles comprise a diameter of about 5 nm to about 17 nm.

Embodiment 33 The method of any one of embodiments 27-32, wherein the solvent of the continuous phase of the colloidal dispersion comprises water.

Embodiment 34 The method of any one of embodiments 27-33, wherein the amount of dispersed phase in the colloidal dispersion ranges from about 5% to about 50% by weight.

Embodiment 35 The method of any one of embodiments 27-33, wherein the amount of dispersed phase in the colloidal dispersion is about 15% by weight.

Embodiment 36 The method of any one of embodiments 27-35, further comprising adding a solution of an inorganic salt to the colloidal dispersion.

Embodiment 37 The method of embodiment 36, wherein the inorganic salt comprises NaCl.

Embodiment 38 The method of embodiment 36 or embodiment 37, wherein the concentration of the inorganic salt in the solution ranges from about 1% w / v to about 30% w / v.

Embodiment 39 The method of any one of embodiments 34-36, wherein the amount of solution of the inorganic salt ranges from about 5% to about 15% by weight relative to the amount of colloidal dispersion.

Embodiment 40 The method of any one of embodiments 27-39, wherein the cationic species comprises a metal cation.

Embodiment 41 The method of embodiment 40, wherein the metal cation comprises two or more oxidation states.

Embodiment 42 The method of embodiment 40 or embodiment 41, wherein the metal cation comprises aluminum or iron.

Embodiment 43. The system of any of embodiments 40-42, wherein the metal cation is Al ₂ O ₃ , Al ₂ (S0 ₄ ) ₃ , KAl (S0 ₄ ) ₂ , FeCl ₃ and Fe ₂ (S0 ₄ ) ₃ And salts or oxides selected from the group consisting of hydrates or solvates thereof.

Embodiment 44 The method of any one of embodiments 27-39, wherein the cationic species comprises a cationic polymer.

Embodiment 45 The compound of embodiment 44, wherein the cationic polymer is poly (2-hydroxypropyl-1-N-dimethylammonium chloride), poly (2-hydroxypropyl-1-1-N-dimethylammonium chloride), Poly [N- (dimethylaminomethyl)]-acrylamide, poly (2-vinylimidazolinium bisulfate), poly (diallyldimethylammonium chloride), poly (N-dimethylaminopropyl) -methacrylamide and these Selected from the group consisting of:

Embodiment 46 The method of embodiment 44, wherein the cationic polymer comprises poly (diallyldimethylammoniumchloride).

Embodiment 47 The method of any one of embodiments 44-46, wherein the cationic polymer has a molecular weight of about 1,000 Da to about 1,000,000 Da.

Embodiment 48 The method of any one of embodiments 44-46, wherein the cationic polymer has a molecular weight of about 1,500 Da to about 500,000 Da.

Embodiment 49 The method of any one of embodiments 44-46, wherein the cationic polymer has a molecular weight of about 1,500 Da to about 100,000 Da.

Embodiment 50 The method of any one of embodiments 44-49, wherein the cationic polymer is water soluble.

Embodiment 51 The method of any one of embodiments 27-39, wherein the cationic species comprises a quaternary ammonium compound.

Embodiment 52 The compound of embodiment 51, wherein the quaternary ammonium compound is 1,2-ethanedianium, N, N'-bis [2- [bis (2-hydroxyethyl) methylammonio] ethyl] -N, N'-bis (2-hydroxyethyl) -N, N'-dimethyl-, tetrachloride.

Embodiment 53 The method of any one of embodiments 27-52, wherein the cationic species is in the form of a solution.

Embodiment 54 The method of embodiment 53, wherein the solution comprises an aqueous solution.

Embodiment 55 The method of embodiment 53 or embodiment 54, wherein the concentration of cationic species in the solution ranges from about 10% to about 50% by weight.

Embodiment 56 The method of any one of embodiments 27-55, wherein the amount of cationic species ranges from about 0.1% to about 2% by weight relative to the amount of colloidal dispersion.

Embodiment 57 The method of any one of embodiments 27-56, wherein the combining step comprises adding a cationic species to the colloidal dispersion.

Embodiment 58 The method of any one of embodiments 27-57, wherein after combining, the reaction mixture is continuously stirred for a time sufficient to obtain coated silica particles.

Embodiment 59 The method of embodiment 58, wherein the amount of time is in the range of about 1 minute to about 15 minutes.

Embodiment 60 The method of any one of embodiments 27-59, wherein the combining step comprises non-covalent linkage of the cationic species to the outer surface of the silica particles.

Embodiment 61 The method of embodiment 60, wherein the noncovalent bond between the cationic species and the outer surface of the silica particles comprises an electrostatic interaction.

Embodiment 62 The method of embodiment 61, wherein the electrostatic interaction comprises attraction between the negatively charged outer surface of the silica particles and the positively charged cationic species.

Embodiment 63 The method of embodiment 62, wherein the electrostatic interaction comprises attraction between the silanol groups or silyloxy anions on the outer surface of the silica particles and the positively charged cationic species.

Embodiment 64 The method of any one of embodiments 27-63, further comprising combining the activator with a colloidal dispersion comprising solid silica particles.

Embodiment 65 The method of embodiment 64, wherein the activator is an alkali silicate.

Embodiment 66 The method of embodiment 65, wherein the alkali silicate is selected from Na-silicate and K-silicate.

Embodiment 67 The coated silica particles produced by the method of any one of embodiments 27-66.

Embodiment 68 A curable delayed gelling composition comprising a particulate material comprising the coated silica particles of any of embodiments 1-26 and 67.

Embodiment 69 The composition of embodiment 68, wherein the amount of particulate matter in the composition is from about 10% to about 50% by weight.

Embodiment 70 The composition of embodiment 68, wherein the amount of particulate material in the composition is about 15% by weight.

Embodiment 71 The composition of any one of embodiments 68-70, further comprising a solvent.

Embodiment 72 The composition of embodiment 71, wherein the solvent comprises water.

Embodiment 73 The composition of embodiment 72, wherein the composition comprises about 50% to about 90% by weight of water.

Embodiment 74 The composition of any one of embodiments 68-73, wherein the pH of the composition ranges from about 9 to about 11.

Embodiment 75 The composition of any one of embodiments 68-74, wherein the viscosity of the composition ranges from about 5 cP to about 10 cP.

Embodiment 76 The composition of any one of embodiments 68-75, further comprising an activator.

Embodiment 77 The composition of embodiment 76, wherein the activator comprises a pH adjuster.

Embodiment 78 The composition of embodiment 77, wherein the pH adjusting agent comprises an ester compound.

Embodiment 79 The composition of embodiment 78, wherein the ester compound is selected from the group consisting of formate esters, lactate esters, and polylactide resins.

Embodiment 80 The composition of embodiment 78, wherein the ester compound is selected from the group consisting of diethylene glycol diformate and ethyl lactate.

Embodiment 81 The composition of any one of embodiments 78-80, wherein the ester compound is hydrolyzed to yield an acid compound.

Embodiment 82 The composition of embodiment 81, wherein the hydrolysis of the ester compound occurs at a temperature of about 75 ° F. to about 350 ° F.

Embodiment 83 The composition of embodiment 81, wherein the hydrolysis of the ester compound occurs at a temperature of about 150 ° F. to about 250 ° F.

Embodiment 84 The composition of any one of embodiments 81-83, wherein hydrolysis of the ester compound reduces the pH of the composition to less than about 5.

Embodiment 85 The composition of any one of embodiments 76-84, wherein the amount of pH adjusting agent in the composition ranges from about 0.25% to about 4% by weight.

Embodiment 86 The composition of embodiment 76, further comprising an ionic strength modifier.

Embodiment 87 The composition of embodiment 86, wherein the ionic strength modifier comprises an inorganic electrolyte.

Embodiment 88 The composition of embodiment 87, wherein the inorganic electrolyte is selected from the group consisting of KCl, NaCl and NaBr.

Embodiment 89 The composition of any one of embodiments 86-88, wherein the amount of ionic strength modifier in the composition is in the range of about 1% to about 5% by weight.

Embodiment 90 The composition of embodiment 76, wherein the activator comprises an alkali silicate.

Embodiment 91 The composition of embodiment 90, wherein the alkali silicate is selected from Na-silicates and K-silicates.

Embodiment 92 The composition of any one of embodiments 76-91, wherein the activator is configured to promote curing of the composition.

Embodiment 93 The composition of any one of embodiments 68-92, wherein the composition is adjusted to form a hard consolidated gel at least 3 hours after the composition is formed.

Embodiment 94 The composition of embodiment 93, wherein the composition is adjusted to form a hard, solidified gel at a temperature of about 75 ° F. to about 350 ° F.

Embodiment 95 The composition of embodiment 93, wherein the composition is adjusted to form a hard consolidated gel at a temperature of about 150 ° F. to about 250 ° F.

Embodiment 96 A method of solidifying a soft underground strata, wherein the method comprises contacting the soft strata with the curable delayed gelling composition of any of embodiments 68-95 to obtain a solidified solid of the underground particles. Method of solidification of phosphorus, soft underground strata.

Embodiment 97 The method of embodiment 96, wherein the contacting step further comprises absorbing the curable delayed gelling composition onto the surface of the unsolidified underground particles.

Embodiment 98 The method of embodiment 97, wherein curing of the composition comprises solidifying the underground particles as a layer of hard gel on the unsolidified underground particles.

Embodiment 99 The method of any one of embodiments 96-98, wherein the underground particles comprise sand grains.

Embodiment 100 The method of any one of embodiments 96-99, wherein the solidified particles of the underground particles are permeable to the fluid.

Embodiment 101 The method of embodiment 100, wherein the solidified mass of underground particles has a strength that withstands a pressure load of at least about 700 lbf.

Embodiment 102 The method of embodiment 101, wherein the solidified particles of the underground particles have a strength to withstand a pressure load of about 700 lbf to about 1000 lbf.

Embodiment 103 The method of any one of embodiments 96-102, wherein the soft underground strata are penetrated by an oil well.

Embodiment 104 The method of embodiment 103, wherein the contacting step comprises delivering the curable delayed gelling composition to the soft underground strata using coil tubing equipment.

Embodiment 105 The method of any one of embodiments 96-104, wherein the soft underground strata comprise a hydrocarbon containing layer.

Embodiment 106 The method of embodiment 105, wherein the hydrocarbon comprises petroleum.

Embodiment 107 The method of embodiment 106, further comprising producing petroleum from the solidified strata.

Other embodiments

While the present application has been described in connection with the detailed description thereof, it should be understood that the foregoing description is intended to illustrate, but not to limit, the scope of the application as defined by the appended claims. Other aspects, advantages, and modifications fall within the scope of the following claims.

Claims (29)

A method of solidifying a soft underground layer, the method comprising contacting a soft ground layer with a curable delayed gelling composition comprising coated silica particles comprising a cationic species non-covalently bound to an outer surface to obtain a solidified particle of the underground particle. How to solidify soft basement. The method of claim 1, wherein the silica particles are nanoparticles comprising a diameter of about 5 nm to about 50 nm. The method according to claim 1 or 2, wherein the cationic species is poly (2-hydroxypropyl-1-N-dimethylammonium chloride), poly (2-hydroxypropyl-1-1-N-dimethylammonium chloride), poly [ N- (dimethylaminomethyl)]-acrylamide, poly (2-vinylimidazolinium bisulfate), poly (diallyldimethylammonium chloride), poly (N-dimethylaminopropyl) -methacrylamide and combinations thereof The method is a cationic polymer selected from the group consisting of. The method of claim 3, wherein the cationic polymer comprises poly (diallyldimethylammoniumchloride). The method of claim 3 or 4 wherein the amount of cationic polymer relative to the weight of the silica particles in the composition is in the range of about 5% to about 20% by weight. The non-covalent bond between the cationic polymer and the outer surface of the silica particles is positively charged with a negatively charged silanol group or silyloxy anion on the outer surface of the silica particles. Electrostatic interactions between the cationic polymers. The method of claim 1, wherein the curable delayed gelling composition comprises water and the amount of particulate matter in the composition is from about 10% to about 50% by weight. The method of claim 1, wherein the pH of the curable delayed gelling composition is in the range of about 9 to about 11. 9. The method of claim 1 or 2, wherein the cationic species comprises a metal cation comprising aluminum or iron. The metal cation of claim 9, wherein the metal cation is selected from the group consisting of Al ₂ O ₃ , Al ₂ (S0 ₄ ) ₃ , KAl (S0 ₄ ) ₂ , FeCl ₃ and Fe ₂ (S0 ₄ ) ₃ , and hydrates or solvates thereof. To form the salt or oxide of choice. The method of claim 9 or 10, wherein the pH of the curable delayed gelling composition is in the range of about 3 to about 5. The method of claim 1, wherein the curable delayed gelling composition comprises an activator configured to promote curing of the composition. The method of claim 12, wherein the activator is a pH adjuster comprising an ester compound and the ester compound is hydrolyzed at a temperature in the range of about 75 ° F. to about 350 ° F. to produce an acid compound. The method of claim 13, wherein the amount of pH adjuster in the composition is in the range of about 0.25% to about 4% by weight. The method of claim 14, wherein the ester compound is selected from the group consisting of formate esters, lactate esters, and polylactide resins. The method of claim 12 wherein the activator is an ionic strength modifier comprising an inorganic electrolyte and the amount of ionic strength modifier in the composition ranges from about 1% to about 5% by weight. The method of claim 12, wherein the activator comprises an alkali silicate. 18. The method of claim 17, wherein the alkali silicate is selected from the group consisting of Na-silicates and K-silicates. The method of claim 1, wherein contacting the soft strata with the curable delayed gelling composition comprises adsorbing the curable delayed gelling composition to the surface of the unsolidified underground particles. 20. The method of claim 19, wherein the non-solidified underground particles comprise sand grains. 21. The method of any one of claims 1-20, wherein the solidified particles of underground particles are permeable to the fluid and have strength to withstand a pressure load of at least about 700 lbf. 22. The method of any one of the preceding claims, wherein contacting the soft layer with the curable delay gelling composition comprises delivering the curable delay gelling composition to the soft underground layer using coil tubing equipment. . 23. The method of any one of claims 1 to 22, wherein the soft underground strata comprise hydrocarbon containing strata and the method comprises producing hydrocarbons from the solidified strata. A method of solidifying a soft subterranean layer, the method comprising contacting the curable delayed gelling composition with the soft layer to obtain solidified particles of the underground particles, wherein the curable delayed gelling composition comprises a cationic polymer non-covalently bound to an outer surface. A method of solidifying a soft underground layer comprising coated silica particles comprising and an activator configured to promote curing of the composition. The method of claim 24, wherein the activator comprises an alkali silicate. The method of claim 25, wherein the alkali silicate is selected from the group consisting of Na-silicates and K-silicates. The method of claim 24, wherein the activator comprises a polyamine. The method of claim 27, wherein the polyamine is 1,2-ethanediamine, N1, N2-bis [2- [bis (2-hydroxyethyl) methylammonio] ethyl] -N1, N2-bis (2-hydroxy Ethyl) -N1, N2-dimethyl-, chloride. The method of claim 24, wherein the activator comprises an alkali silicate and a polyamine.

Images